Harvard Dialect Survey · spoken edition
The dialect quiz at mydialect.us asks you to pick answers off a list. This one asks you to talk. You read short lines aloud; where a word is up to you, the line stops and leaves you a gap to fill with whatever you'd actually say.
Everything you say is measured on this device — vowel formants, sibilant spectra, syllable nuclei, voicing — and turned into an IPA reading, which picks your answer for you. Nothing is uploaded except the speech-recognition transcript, which the browser handles.
On iPhone and iPad, use Safari itself. Every iOS browser runs on WebKit, but speech recognition is Safari's own — Chrome, Firefox and in-app browsers don't get it, and neither does a Home Screen shortcut. The 36 pronunciation questions work in any of them, since those are measured from the audio; the 24 word questions need Safari, or a tap. Turn on Settings → General → Keyboard → Enable Dictation, and expect to tap once to start each line: iOS only opens the microphone from a gesture, and hands it to one thing at a time.